Fuel injection controlling system for internal combustion engine

ABSTRACT

A fuel injection controlling system wherein fuel injectors each thereof associated with each one of cylinders are grouped in correspondence with each two of the cylinders, each group of the fuel injection controlling valves are opened only when it is desired that fuel be injected with respect to one of each corresponding group of cylinders, and at the starting point of the engine all the valves belonging to one group are opened when it is desired that fuel injection be effected with respect to any one of the two cylinders belonging to the corresponding group.

C United States Patent [151 3,659,565 Kasama et al. [451 May 2, 1972 FUEL INJECTION CONTROLLI G 3,181,520 5/1965 Mock ..123/32 E SYSTEM FOR INTERNAL 3,430,616 3/1969 Glockler ..123/32 E COMBUSTION ENGINE 3,463,130 8/1969 Reichardt et a] ..123/179 A 3,483,851 12/1969 Reichardt ..123/32 E [72] lnventors: Ryoji Kasama; Se1 l Suda, both of Hitachishr, Japan Primary Examiner-Laurence M. Goodridge [73] Assignee: Hitachi, Ltd., Tokyo, Japan A!t0rneyCraig, Antonelli & Hill [22] F1led: May 2, 1969 ABSTRACT [21] Appx' 821,180 A fuel injection controlling system wherein fuel injectors each thereof associated with each one of cylinders are grouped in [30] F r ig pplica ion Priority Data correspondence with each two of the cylinders, each group of May 6 1968 Japan ..43/29871 fuel valves are Pened when is desired that fuel be injected with respect to one of each cor- 52 US. c1. ..123 32 EA, 123 119, 123 179 A responding group of cylinders, and at the Starting Point of the [51] Int. Cl ..F02d 5/00 engine the Valves belonging to one group are opened when [58] Field of Search ,123/32, 32 E, 1 19, 179 G, 179 1,, it is desired that fuel injection be effected with respect to any 123/179 A one of the two cylinders belonging to the corresponding group. [56] References Cited 4 Claims, 2 Drawing Figures UNITED STATES PATENTS 3,356,896 12/1967 Shano ..123/148 E X COM- 4 I FUEL INJECTION CONTROLLING SYSTEM FOR INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a fuel injection controlling system for an internal combustion engine, and more particularly it pertains to such system adapted to exhibit an improved fuel feeding performance at the starting of the engine.

2. Description of the Prior Art The well-known means for feeding fuel to an engine is of the fuel injection type wherein fuel is injected into a suction manifold with the aid of a fuel injection pump and the quantity of injected fuel is controlled in accordance with the running conditions of the engine. The use of an electromagnetic valve as control valve is convenient because it may be controlled in accordance with a result obtained by computing electrical signals into which the various conditions of the engine are converted. In such a case, ideally, one electromagnetic valve is provided for each cylinder, and each electromagnetic valve is opened while the intake valve is opened to thereby permit the supply of the required quantity of fuel. In view of the durability and cost of such electromagnetic valves, however, limitation is laid on the response characteristic thereof, and therefore difficulty is encountered in attempting to inject fuel during the opened interval of the intake valve when the engine is at a high speed of rotation.

In order to avoid such drawbacks, there has been proposed a method to simultaneously open several of the electromagnetic valves associated with the cylinders. For example, in case two electromagnetic valves associated with two cylinders are simultaneously opened, then the opening time (injection time) is synchronized with that of the intake valve associated with either one of the cylinders. In this case, the other cylinder is supplied with fuel when the intake valve is closed. Under ordinary running conditions however, fuel can be supplied to the cylinder without any trouble. At the starting point, on the other hand, the phenomenon is observed that the fuel supply condition for the cylinders is deteriorated so that the starting performance of the engine is extremely degraded, due, among others, to the fact that the intake efficiency becomes low because the engine temperature is low.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a fuel injection controlling system of the type wherein a plurality of electromagnetic valves associated with a plurality of cylinders are simultaneously opened to inject fuel, thereby irnproving the starting performance of an engine.

Another object of the present invention is to provide a fuel injection controlling system adapted to make it possible to feed an increased quantity of fuel at the starting point of an engine.

Still another object of the present invention is to provide a fuel injection controlling system which is capable of automatically correcting the quantity of fuel supplied at the starting point of an engine.

Other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

In accordance with the present invention, there is provided a fuel injection controlling system wherein fuel injection controlling valves associated with respective cylinders are grouped in such a manner that each one group includes a plurality of such valves and the valves belonging to any one group are simultaneously opened to permit fuel feed when it is desired that fuel injection be effected with respect to one of the cylinders belonging to the corresponding group, characterized in that at the starting point of an engine, fuel is fed by opening the control valves corresponding to the plural cylinders when it is desired that fuel injection be effected with respect to each of the cylinders.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an embodiment of the present invention; and

FIG. 2 is a view showing a fuel injection control program.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 illustrates a fuel injection control program for a fourcycle, four-cylinder type internal combustion engine wherein the fuel is injected by opening electromagnetic valves each two of which is associated with each two of the four cylinders. In this example, the control is performed so that fuel injection is effected simultaneously with respect to the first and second cylinders and simultaneously with respect to the third and fourth cylinders. More specifically, fuel is injected into the pair of first and second cylinders at the suction stroke of the second cylinder and into the pair of third and fourth cylinders at the suction stroke of the third cylinder. Further, the design is made such that the injection is initiated when distributor contacts are closed which are actuated in synchronism with the rotation of the engine crankshaft and the quantity of fuel to be injected is controlled in a computed manner in ac cordance with the various running conditions of the engine. Main injection is effected only at the suction stroke of the second and third cylinders, and starting compensation injection is efiected at the suction stroke of the first and fourth cylinders in addition to the main injection. The main and starting compensation injections at the starting point are controlled in synchronism with ignition breaker contacts so that they are initiated when these contacts are opened.

Referring now to FIG. 1, description will be made of an embodiment of the present invention, wherein numeral 1 represents a computing circuit adapted to compute the necessary quantity of fuel (the quantity of fuel to be supplied) in accordance with condition signals available from the engine when a voltage applied to a gate terminal 2 thereof disappears. This circuit 1 may be constituted by an operational amplifier, level discriminating circuit such as a Schmitt circuit or the like and saw-tooth wave sweep circuit, wherein a fuel quantity computing condition signal available from the engine 3 and a saw-tooth wave sweep signal voltage are applied to the input terminal of the operational amplifier, and a time-width output signal representing the quantity of fuel to be supplied is obtained at the output terminal 4 in synchronism with synchronizing signals. It will be apparent however that the computing circuit 4 may be constructed in any other form if necessary. The output signal supplied to the output terminal 4 is imparted to base electrodes of transistors 7 and 8 through resistors 5 and 6 respectively so that the conductive condition is established between the emitter and collector electrodes of each of the transistors so that current is caused to flow through electromagnetic coils 9, l0 and 11, 12 adapted to operate electromagnetic valves. The electromagnetic coils 9 and 10 are adapted to serve as electromagnetic coils for the electromagnetic valves which are associated with the first and second cylinders, and connected between the collector electrode of the transistor 7 and a conductor 13. The electromagnetic coils 11 and 12 are adapted to serve as electromagnetic coils for the electromagnetic valves which are associated with the third and fourth cylinders, and connected between the collector electrode of the transistor 8 and the conductor 13. The

conductor 13 is connected with a battery 15 through a power source switch 14. Numerals 16 and 17 represent distributor contacts of switches which are operated by a cam adapted to rotate in synchronism with the crankshaft of the engine and which are set up to be closed when crank angle 0 is reached which corresponds to that at which fuel injection is to be effected. The distributor switch 16 is associated with the first and second cylinders, and the distributor switch 17 is associated with the third and fourth cylinders. Each of the switches 16 and 17 have one contact thereof grounded and the other contact thereof connected with the conductor 13 through resistors 18 and 19 respectively. Further, the ungrounded contacts of the switches 16 and 17 are connected with base electrodes of transistors 22 and 23 through resistors 20 and 21 respectively. The transistors 22 and 23 have the emitter electrodes thereof grounded and the collector electrodes thereof connected with the conductor 13 through resistors 24 and 25 and also with base electrodes of transistors and 31 through diodes 28 and 29 respectively. The transistors 30 and 31 constitute a bistable flip-flop circuit wherein the emitter electrodes of the transistors 30 and 31 are grounded and the collector electrodes thereof are connected with the conductor 13 through resistors 32 and 33 and with each other's base electrode through resistors 34 and 35 respectively. Further, the collector electrodes of the transistors 30 and 31 are connected with the base electrodes of the transistors 7 and 8 through diodes 36 and 37 respectively. The connection is set up so that the voltage at the conductor 13 is imparted to the collector electrode of a transistor through resistors 38 and 39 and also to the gate terminal of the computing circuit 1 through a resistor 41. The connection point between the resistors 38 and 39 is connected with the non-grounded contacts of the distributer switches 16 and 17 through diodes 42 and 43 respectively. Numeral 44 denotes an ignition transformer having primary and secondary coils 45 and 46 connected with each other at one end and grounded through a breaker point 47. The other end of the primary coil 45 is connected with the conductor 13, and the other end of the secondary coil 46 is connected with an ignition spark plug 48. A transistor 49 is provided which has the emitter electrode thereof grounded, the base electrode thereof connected with the conductor 13 through resistors 50 and 51 the connection point between which is connected with the non-grounded contact of the breaker point through diode 52, and the collector electrode thereof connected with the connection point between resistors 53 and 54. The other end of theresistor 53 is coupled to the gate terminal 2 of the computing circuit 1 through a diode 55, and the other end of the resistor 54 is connected with the conductor 13 through a diode 56 and starter switch 57. That contact of the starter switch 57 which is opposite to the conductor 13 is grounded through electromagnetic coil 59 of an electromagnetic switch 58 and also with the base electrode-of the aforementioned transistor 40 through a resistor 60. Numeral 61 indicates a starter motor having one terminal grounded and another terminal connected with the conductor 13 through contact 62 of the electromagnetic switch 58. g

g In the foregoing arrangement, the power source switch 14 is closed at the starting point so that the various electric circuits are energized. Upon closure of the starter switch 57, the electromagnetic coil 59 is energized'so that the switch 62 is closed. Thus, the engine is driven by the starter motor 61. At the same time, a current is caused to flow into the base electrode of the transistor .40 through the resistor 60 so that the conducting state is established between the emitter and collector electrodes thereof. Consequently, the connection point between the resistors 39 and 41 is grounded. At this point, a voltage is imparted to the gate terminal 2 of the computing circuit 1 through the diode 56, resistors 54 and 53 and diode 55. In this state, the breaker point 47 remains closed, and therefore a current to be supplied to the base electrode of the transistor 49 is caused to flow from the resistor 51 to the ground through the diode 52 and breaker point 47. Thus, the transistor 49 is in the non-conducting state. At such a stage, if the crankshaft is rotated to open the break point 47, then the current having been flowing through the resistor 51 is made to flow in the base electrode of the transistor 49 through the resistor 50, whereby the conducting state is established between the emitter and collector electrodes of the transistor 49. Consequently, the voltage which has been imparted to the gate terminal 2 of the computing circuit 1 when 49 is non-conducting due to the voltage drop across 41, vanishes. In this way, the computing circuit 1 provides an output voltage having a time width corresponding to the required fuel quantity at the output terminal, in accordance with the condition signal available from the engine. If the third cylinder is at the intake stroke at this point, then the distributor switch 16 is in the open state while the distributor switch 17 is in the closed state. Thus, the non-conducting state is established between the emitter and collector electrodes of the transistor 23, with a high potential maintained at the collector electrode. In the bistable flip-flop circuit, therefore, the transistor 31 is rendered conductive while the transistor 30 is rendered non-conductive. In this state, since the base electrode of the transistor 7 is grounded through the diode 37 and transistor 31, only the transistor 8 is rendered conductive by the output voltage appearing at the output terminal 4 of the computing circuit 1 so that a current is caused to flow through the electromagnetic coils l1 and 12 whereby the electromagnetic valve associated with the third and fourth cylinders. Thus, fuel injection is effected with respect to the third and fourth cylinders. This is main injection. The reason why the breaker point 47 is opened to ignite the second cylinder. A 180 rotation of the crankshaft brings the first cylinder into the explosion stroke. At this point, too, the breaker point 47 is opened and therefore the voltage at the gate terminal 2 disappears so that an output voltage appears at the output terminal 4 of the computing circuit 1 as in the previous stroke. At this point, however, since the distributor switch 17 is still in the closed state, fuel injection is effected with respect to the third and fourth cylinders. This is the corrected injection.

A further l80 rotation of the crankshaft brings the third cylinder into the explosion stroke, and therefore the breaker point 47 is opened so that an output voltage appears at the output terminal 4 of the computing circuit. At this point, since the distributer switch 17 is opened and the switch 16 is closed, the transistor 30 of the bistable flip-flop circuit is rendered conductive. Thus, the transistor 7 is also rendered conductive by the output voltage of the flip-flop circuit, so that the electromagnetic coils 9 and 10 are energized to open the corresponding electromagnetic valves, with the result that fuel injection is effected with respect to the first and second cylinders. Fuel injection which is efi'ected when the crankshaft is further rotated through 180 will be readily appreciated from the foregoing.

When the engine is brought into the running condition by opening the starter switch 57, the transistor 40 is rendered non-conductive because the base current thereof is interrupted. Also, the voltage which has been imparted to the gate terminal 2 of the computing circuit 1 through the diode disappears. Instead, the voltage at the conductor 13 is applied to the gate terminal 2 through resistors 38, 39 and 41. in such a state, the voltage at the gate terminal disappears when either one of the distributor switches 16 and 17 is closed so that the connection point between the resistors 38 and 39 is grounded through the diodes 42 and 43. Thereupon, fuel injection is effected. This fuel injection includes only the main injection shown in the injection program of FIG. 2.

In the foregoing embodiment, the fuel injection at the start ing point was effected by the use of the firing breaker point. However, it will be readily apparent to those skilled in the art that such injection can also be effected by the use of separately provided contacts. It is to be understood that the present invention is by no means limited to the foregoing embodiment. Various changes and modifications will become possible without departing from the spirit of the present invention and the scope of the appended claims. Of course, such changes and modifications will constitute part of the present invention.

What is claimed is:

1. A fuel injection controlling system for an internal combustion engine comprising:

a first and second distributor means each generating energizing signals in synchronism with rotation of the engine crankshaft a plurality of electromagnetic valves for feeding fuel into each intake manifold corresponding to each cylinder of the internal combustion engine,

a computing circuit for generating a pulse having duration corresponding to the condition of the internal combustion engine for controlling the quantity of fuel by varying the opening duration of said electromagnetic valves,

first means for passing currents concurrently based on an output pulse of said computing circuit through electromagnetic coils of said plurality of electromagnetic valves in each of the groups into which said plurality of electromagnetic valves are segregated so as to be operated in groups,

second means responsive to the energizing signals of said first distributor for actuating said computing circuit when cylinders in one of said groups of electromagnetic valves have reached a predetermined fuel injection time according to the stroke of the internal combustion engine,

third means responsive to the energizing signals of said second distributor means which are a multiple timed signal with respect to the timed signals of said first distributor means for actuating said computing circuit when each cylinder in one of said groups of electromagnetic valves has reached a predetermined fuel injection time according to the stroke of the internal combustion engine during cranking of said internal combustion engine, and fourth means operated during engine cranking for enabling said third means and disabling said second means and for enabling said second means and disabling said third means during engine operation.

2. A fuel injection controlling system for an internal combustion engine according to claim 1, further comprising electrical starting means for engine cranking and said second distributor means being electrical ignition means for generating an ignition spark in a predetermined stroke of each cylinder.

3. A fuel injection controlling system for an internal combustion engine comprising:

a first and second distributor means each generating energizing signals in synchronism with rotation of the engine crankshaft.

a plurality of electromagnetic valves for feeding fuel into each intake manifold corresponding to each cylinder of the internal combustion engine,

a computing circuit for generating a pulse having a duration corresponding to the condition of the internal combustion engine for controlling the quantity of fuel by varying the opening duration of said electromagnetic valves,

a plurality of means for passing currents concurrently based on an output pulse of said computing circuit through electromagnetic coils of said plurality of electromagnetic valves in each of the groups into which said plurality of electromagnetic valves are segregated so as to be operated in groups,

means responsive to the energizing signals of said first distributor means. for selecting 'one of said plurality of means for passing currents through the electromagnetic coils of the electromagnetic valves when cylinders in one of said groups of electromagnetic valves have reached a predetermined fuel injection time for giving the output pulse from said computing circuit according to the stroke of the internal combustion engine, and also for actuating said computing circuit, and

means responsive to the energizing signals of said second distributor means which are a multiple timed signal with respect to the timed signals of said first distributor means. for actuating said computing circuit when each cylinder in one of said groups of electromagnetic valves has reached a predetermined fuel injection time according to the stroke of the internal combustion engine during cranking of the internal combustion engine, and

fourth means operated during cranking for enabling said third means and disabling said second means, and for enabling said second means and disabling said third means during engine operation.

4. A fuel injection controllin system according to claim 3}, further comprising electric starting means for cranking the engine and said second distributor means being electrical ignition means for generating an ignition spark in a predetermined stroke of each cylinder.

* IIK 

1. A fuel injection controlling system for an internal combustion engine comprising: a first and second distributor means each generating energizing signals in synchronism with rotation of the engine crankshaft a plurality of electromagnetic valves for feeding fuel into each intake manifold corresponding to each cylinder of the internal combustion engine, a computing circuit for generating a pulse having duration corresponding to the condition of the internal combustion engine for controlling the quantity of fuel by varying the opening duration of said electromagnetic valves, first means for passing currents concurrently based on an output pulse of said computing circuit through electromagnetic coils of said plurality of electromagnetic valves in each of the groups into which said plurality of electromagnetic valves are segregated so as to be operated in groups, second means responsive to the energizing signals of said first distributor for actuating said computing circuit when cylinders in one of said groups of electromagnetic valves have reached a predetermined fuel injection time according to the stroke of the internal combustion engine, third means responsive to the energizing signals of said second distributor means which are a multiple timed signal with respect to the timed signals of said first distributor means for actuating said computing circuit when each cylinder in one of said groups of electromagnetic valves has reached a predetermined fuel injection time according to the stroke of the internal combustion engine during cranking of said internal combustion engine, and fourth means operated during engine cranking for enabling said third means and disabling said second means and for enabling said second means and disabling said third means during engine operation.
 2. A fuel injection controlling system for an internal combustion engine according to claim 1, further comprising electrical starting means for engine cranking and said second distributor means being electrical ignition means for generating an ignition spark in a predetermined stroke of each cylinder.
 3. A fuel injection controlling system for an internal combustion engine comprising: a first and second distributor means each generating energizing signals in synchronism with rotation of the engine crankshaft. a plurality of electromagnetic valves for feeding fuel into each intake manifoLd corresponding to each cylinder of the internal combustion engine, a computing circuit for generating a pulse having a duration corresponding to the condition of the internal combustion engine for controlling the quantity of fuel by varying the opening duration of said electromagnetic valves, a plurality of means for passing currents concurrently based on an output pulse of said computing circuit through electromagnetic coils of said plurality of electromagnetic valves in each of the groups into which said plurality of electromagnetic valves are segregated so as to be operated in groups, means responsive to the energizing signals of said first distributor means. for selecting one of said plurality of means for passing currents through the electromagnetic coils of the electromagnetic valves when cylinders in one of said groups of electromagnetic valves have reached a predetermined fuel injection time for giving the output pulse from said computing circuit according to the stroke of the internal combustion engine, and also for actuating said computing circuit, and means responsive to the energizing signals of said second distributor means which are a multiple timed signal with respect to the timed signals of said first distributor means. for actuating said computing circuit when each cylinder in one of said groups of electromagnetic valves has reached a predetermined fuel injection time according to the stroke of the internal combustion engine during cranking of the internal combustion engine, and fourth means operated during cranking for enabling said third means and disabling said second means, and for enabling said second means and disabling said third means during engine operation.
 4. A fuel injection controlling system according to claim 3, further comprising electrical starting means for cranking the engine and said second distributor means being electrical ignition means for generating an ignition spark in a predetermined stroke of each cylinder. 